It is known that a conventional electrostatic recording element is provided with a substrate, such as paper, a conductive layer located on a surface of the substrate and containing a cationic or anionic polyelectrolyte substance, and a dielectric layer with an electrostatic recording surface. This type of conventional electrostatic recording element is useful for forming clear electrostatic images on the recording surface under ordinary atmospheric conditions. However, since the cationic or anionic polyelectrolyte substance highly hydrophilic, the conventional recording element exhibits the following disadvantages.
1. In an ambient atmosphere having a low temperature of, for example, 20.degree. C. or less, and/or a low humidity of, for example, 30% RH or less, the cationic or anionic polyelectrolyte substance exhibits a very low degree of electrolysis, which causes the conductive layer to exhibit a very low conductivity, and therefore, the recording element cannot form clear electrostatic images thereon. Accordingly, during the winter seasons in the cold and temperate latitudes, the quality of the clearness of the electrostatic images on the recording surface becomes poor and, sometimes, the background of the images is soiled.
2. In another ambient atmosphere having a high temperature of, for example, 30.degree. C. or more and/or a high humidity of, for example, 75% RH or more, the polyelectrolyte substrate absorbs moisture from the ambient atmosphere and migrates into the substrate and/or the dielectric layer, which causes the conductivity of the conductive layer to be excessively high and the resolution power of the recording element to be very poor. Accordingly, during the summer season in the temperate latitudes and during the rainy season in the tropical latitudes, the images formed on the recording element are frequently unclear and/or deformed
In order to eliminate the above-mentioned disadvantages from the conventional electrostatic recording element, attempts have been made to replace the cationic or anionic polyelectrolyte substance with an electron electro-conductive agent, such as metals, for example, powered stainless steel, silver and copper, carbon black, electroconductive stannic oxide and titanium dioxide, and copper iodide. However, the powdered metals are disadvantageous in that the resultant recording element is undesirably colored and some of the metals per se are toxic or harmful to the human body. The carbon black causes the resultant recording element to be significantly colored. The electroconductive stannic oxide tends to corrode some metallic material and is very expensive. The electroconductive titanium dioxide exhibits a relatively high specific resistivity, undesirably colors the recording element and is very expensive. Moreover, the copper iodide is highly unstable so that the conductivity of the resultant conductive layer alters with changes in the ambienet atmospheric humidity and temperature, and is deteriorated during a long period of storage. Also, the copper iodide exhibits a toxicity to the human body and is corrosive to some metallic materials. Furthermore, the copper iodide causes the resultant recording element to be undesirably colored.